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I had a 2012 outback which used 5w-30 synthetic oil, now I have a 2015 out which uses 0w-20 synthetic oil. I have a bit of 5w-30 oil left and I was wondering if I can mix 1 liter of 5w-30 to my 4 liters of 0w-20 oil.
 

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2018 Legacy 36R
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Shouldn't be a problem. I've done that before in my Accord, I think you will come out with an oil that's just a little heavier than 0W20 which won't hurt a thing.
 

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2016 3.6 Limited with ES
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Have fun. Your car and mileage will never know.

If you want to another discussion on a different day, we can talk about upping the viscosity to a thin 30 wt instead of staying with the 20 wt.
 

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Use it up, then you can just buy 5 quart jugs and have no more leftovers!
 

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Have fun. Your car and mileage will never know.

If you want to another discussion on a different day, we can talk about upping the viscosity to a thin 30 wt instead of staying with the 20 wt.
how about coors regular vs. coors lite,...and mixing them?
 

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how about coors regular vs. coors lite,...and mixing them?
OK for beer batter, but that's about it. Even at full strength.
 

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OK for beer batter, but that's about it. Even at full strength.
blackstone labs. has a untapped market, Used Beer Analysis. (I guess shipping plastic jars of piss in the mail is OK ).

but the goal would be something that does not give you a beer gut,...but still does not drink like water.
 

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Shouldn't be a problem. I've done that before in my Accord, I think you will come out with an oil that's just a little heavier than 0W20 which won't hurt a thing.
Would this also apply to the 2019 Ascent? It uses 0w20 ....There is discussion elsewhere that indicates that it was designed for 0w20 and it needs that to get that lubrication into it’s smaller tolerances...sorry If that is stated oddly, I don’t know much about Car engines, mechanical stuff...
 

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blackstone labs. has a untapped market, Used Beer Analysis. (I guess shipping plastic jars of piss in the mail is OK ).

but the goal would be something that does not give you a beer gut,...but still does not drink like water.
I suggest the 7% solution; either Bell's Two Hearted Ale or Founder's Centennial.
Big fan of augmented reality.
 

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Would this also apply to the 2019 Ascent? It uses 0w20 ....There is discussion elsewhere that indicates that it was designed for 0w20 and it needs that to get that lubrication into it’s smaller tolerances...sorry If that is stated oddly, I don’t know much about Car engines, mechanical stuff...

In my opinion it wouldn't hurt a thing if you mixed some 5W30 with 0W20. In fact you could probably use 5W30 once the warranty has expired (or maybe before). As far as I know there is no evidence that the 0W20 recommendation is due to anything but an EPA requirement that the recommended oil be the same weight as the oil used during mileage and emissions testing. If you could find an owner's manual for the same engine from a country that does not have our EPA requirement you might find that they recommend 5W30.


I do not use Amsoil but it is a good product and they have a lot of good information on their site about oil weight and requirements, take a look at this for example: Truth about 5w-20 and 0W-20 Motor Oil - technical facts
 

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just checked the subaru uk site for a manual, and pulled up the 2017, as that is what i have. it says that 0w20 is the factory fill and used for better millage. 5w30 and 5w40 can also be used.
 

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Have fun. Your car and mileage will never know.

If you want to another discussion on a different day, we can talk about upping the viscosity to a thin 30 wt instead of staying with the 20 wt.
Such as? Will look for a 0W or 5W-30 when my warranty period is up.
 

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Yes, just that. Pennzoil Platinum is a thin 30 or Valvoline Advanced also in 5w-30. Both syn oils.

If you are in that part of NorCal where it's truly -10 or more, consider M1 AFE 0w-30.

Myself I'm in SoCal and doing desert trips to AZ so I use M1 0w-40. Consumption hasn't changed and neither has my mileage, as far as my hand calculations can tell. Add in a cargo box too.
 

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Yes, just that. Pennzoil Platinum is a thin 30 or Valvoline Advanced also in 5w-30. Both syn oils.

If you are in that part of NorCal where it's truly -10 or more, consider M1 AFE 0w-30.

Myself I'm in SoCal and doing desert trips to AZ so I use M1 0w-40. Consumption hasn't changed and neither has my mileage, as far as my hand calculations can tell. Add in a cargo box too.
That doesn't make any sense... 30 weight is the viscosity...
 

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That doesn't make any sense... 30 weight is the viscosity...

It does make sense and the industry standards allow them to produce a 30wt oil that can have different viscosities while still claiming, rightfully so, they are within the 30 wt spec.

According to the Society of Automotive Engineers (SAE) a 30 wt oil must have its viscosity fall within the following:

Not less than 9.3 cSt at 100C and not more than 12.5 cSt at 100C. That's a large spread however any oil that falls within the grade meets spec and can be used in a car specifying a 30 wt oil.

Taking it to real world oil numbers from the manufacturer's own sites, the Pennzoil Platinum 5w-30 I recommended has a 9.8 cSt value at 100C. That's barely within the grade and very close to a 20 wt oil which must have a value of less than 9.3.

On the thicker side, Castrol 0w-30 posts specs on their site showing a 12.3 cSt value. That's almost a 40 wt but still within the 30 wt requirement. The M1 0w-40 I'm currently running has a 12.9 cSt value which is nearly a 30 wt but if have any fuel dilution or shearing, it's solidly a 30 wt and within spec.

Thinner oils are supposed to help with mileage while affording protection and thicker helps with protection while taking a tick off of mileage. If you tow, run at hot ambient temps with a loaded car or run up grades the manual suggests a change to a thicker viscosity however as you can see, just changing to a thicker weight within grade will work.

For a 2.5 that requires a 20 wt oil, as you can see there is very little diffence between a 20 and 30 wt oils at 100C. Most 2.5s run a little hotter but 100C is the industry standard for measurement so a 20 wt is little thinner hence the thin 30 wt recomnendation.

This oil world is a crazy place but there's room, without running into warranty problems, to use a thinner or thicker oil within the requested spec.


EDIT for additional info:


To illustrate the differences at oil temp the industry uses 100C but from browsing this site numerous posts over the years have people reporting various oil temps on the 2.5 engines. A lot are less than 205F, some are higher at over 210, some spike even higher for brief periods and I'm using a guesstimate or WAG of 217F for illustration purposes. A search of posts shows a lot of different temps and 217 is not outside of the curve.



Using the Widman viscosity calculator one enters the 40C and 100C cSt values and then the temp for which you want to find the new value.


With the Pennzoil Platinum 5w-30 the respective values are 53.9 and 9.8 to start with.


217 converted is 103C and plugging that figure in, if your car runs at 217 the new cSt value is 9.2. That's a 20 wt oil viscosity. There may be other things in the oil that offer protection that are organic or not measurable by an ordinary UOA however if one focuses on a specific viscosity requirement, a thin 30 wt is very appropriate for the 2.5.
 

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Would I mix while under warranty? Nope.

Would I do that after warranty? Without a 2nd thought.
 

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i find it interesting that the uk model can run the 3 different types. they only recommend 0w20 for better gas mileage. i would for my car to run 5w30 as its easier to find and have run it in all my cars without problems.
 

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5W30 used all the time!!!

just checked the subaru uk site for a manual, and pulled up the 2017, as that is what i have. it says that 0w20 is the factory fill and used for better millage. 5w30 and 5w40 can also be used.
I live in Phoenix AZ I run 5W30 oil all the time. Temps are higher here runs great with 5W30.

Extreme condition everyday in Phoenix!!!


EPA 0W20 better gas mileage!!! Make manufacture have better #’s. Fuji Heavy Industries
 

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ive been thinking of using that when i change my oil. used it in all my past cars without any issues. ive even considered maybe 5w20 just to stay with the 20. good to know in extreme it works well.
 
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